I got a lumia 510 last week and am quite happy with the phone functions and features when compared to its affordable price. But over the last few days I have noticed two issues on my phone. One thing is that during calls I feel that voice clarity is not so good and that there is a slight voice break at times. Another issue is that sometimes when I make calls or get incoming calls the earpiece just doesn't work but I can hear the voice of the person on the other side of the call if I use a headset and this problem vanishes as soon as I restart the phone. Is this a relatively common issue that other Lumia 510 users are facing and not worry about it or take it to a Nokia care centre for service?